Vehicle Safety Communications E-Book

Tao Zhang

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Serie: Information and Communication Technology
• Sprache: Englisch

Seitenzahl: 593

Veröffentlichungsjahr: 2012

Beschreibung

Provides an up-to-date, in-depth look at the current research, design, and implementation of cooperative vehicle safety communication protocols and technology Improving traffic safety has been a top concern for transportation agencies around the world and the focus of heavy research and development efforts sponsored by both governments and private industries. Cooperative vehicle systems--which use sensors and wireless technologies to reduce traffic accidents--can play a major role in making the world's roads safer. Vehicle Safety Communications: Protocols, Security, and Privacy describes fundamental issues in cooperative vehicle safety and recent advances in technologies for enabling cooperative vehicle safety. It gives an overview of traditional vehicle safety issues, the evolution of vehicle safety technologies, and the need for cooperative systems where vehicles work together to reduce the number of crashes or mitigate damage when crashes become unavoidable. Authored by two top industry professionals, the book: * Summarizes the history and current status of 5.9 GHz Dedicated Short Range Communications (DSRC) technology and standardization, discussing key issues in applying DSRC to support cooperative vehicle safety * Features an in-depth overview of on-board equipment (OBE) and roadside equipment (RSE) by describing sample designs to illustrate the key issues and potential solutions * Takes on security and privacy protection requirements and challenges, including how to design privacy-preserving digital certificate management systems and how to evict misbehaving vehicles * Includes coverage of vehicle-to-infrastructure (V2I) communications like intersection collision avoidance applications and vehicle-to-vehicle (V2V) communications like extended electronic brake lights and intersection movement assist Vehicle Safety Communications is ideal for anyone working in the areas of--or studying--cooperative vehicle safety and vehicle communications.

Leseprobe

Table of Contents

COVER

WILEY SERIES ON INFORMATION AND COMMUNICATION TECHNOLOGY

TITLE PAGE

COPYRIGHT PAGE

FOREWORD

FOREWORD

FOREWORD

PREFACE

BOOK OUTLINE

ACKNOWLEDGMENTS

1 TRAFFIC SAFETY

1.1 TRAFFIC SAFETY FACTS

1.2 EUROPEAN UNION

1.3 JAPAN

1.4 DEVELOPING COUNTRIES

2 AUTOMOTIVE SAFETY EVOLUTION

2.1 PASSIVE SAFETY

2.2 ACTIVE SAFETY

2.3 ADVANCED DRIVER ASSISTANCE SYSTEMS

2.4 COOPERATIVE SAFETY

3 VEHICLE ARCHITECTURES

3.1 ELECTRONIC CONTROL UNITS

3.2 VEHICLE SENSORS

3.3 ONBOARD COMMUNICATION NETWORKS

3.4 VEHICLE DATA

3.5 VEHICLE DATA SECURITY

3.6 VEHICLE POSITIONING

4 CONNECTED VEHICLES

4.1 CONNECTED VEHICLE APPLICATIONS

4.2 UNIQUENESS IN CONSUMER VEHICLE NETWORKS

4.3 VEHICLE COMMUNICATION MODES

4.4 WIRELESS COMMUNICATIONS TECHNOLOGY FOR VEHICLES

5 DEDICATED SHORT-RANGE COMMUNICATIONS

5.1 THE 5.9 GHZ SPECTRUM

5.2 DSRC IN THE EUROPEAN UNION

5.3 DSRC IN JAPAN

5.4 DSRC STANDARDS

6 WAVE PHYSICAL LAYER

6.1 PHYSICAL LAYER OPERATIONS

6.2 PHY AMENDMENTS

6.3 PHY LAYER MODELING

7 WAVE MEDIA ACCESS CONTROL LAYER

7.1 MEDIA ACCESS CONTROL LAYER OPERATIONS

7.2 MAC LAYER AMENDMENTS

7.3 MAC LAYER MODELING

7.4 OVERHAULED NS-2 IMPLEMENTATION

8 DSRC DATA RATES

8.1 INTRODUCTION

8.2 COMMUNICATION DENSITY

8.3 OPTIMAL DATA RATE

9 WAVE UPPER LAYERS

9.1 INTRODUCTION

9.2 DSRC MULTICHANNEL OPERATIONS

9.3 PROTOCOL EVALUATION

9.4 WAVE SHORT MESSAGE PROTOCOL

10 VEHICLE-TO-INFRASTRUCTURE SAFETY APPLICATIONS

10.1 INTERSECTION CRASHES

10.2 COOPERATIVE INTERSECTION COLLISION AVOIDANCE SYSTEM FOR VIOLATIONS

10.3 INTEGRATED SAFETY DEMONSTRATION

11 VEHICLE-TO-VEHICLE SAFETY APPLICATIONS

11.1 COOPERATION AMONG VEHICLES

11.2 V2V SAFETY APPLICATIONS

11.3 V2V SAFETY APPLICATIONS DESIGN

11.4 SYSTEM IMPLEMENTATION

11.5 SYSTEM TESTING

12 DSRC SCALABILITY

12.1 INTRODUCTION

12.2 DSRC DATA TRAFFIC

12.3 CONGESTION CONTROL ALGORITHMS

12.4 CONCLUSIONS

13 SECURITY AND PRIVACY THREATS AND REQUIREMENTS

13.1 INTRODUCTION

13.2 ADVERSARIES

13.3 SECURITY THREATS

13.4 PRIVACY THREATS

13.5 BASIC SECURITY CAPABILITIES

13.6 PRIVACY PROTECTIONS CAPABILITIES

13.7 DESIGN AND PERFORMANCE CONSIDERATIONS

14 CRYPTOGRAPHIC MECHANISMS

14.1 INTRODUCTION

14.2 CATEGORIES OF CRYPTOGRAPHIC MECHANISMS

14.3 DIGITAL SIGNATURE ALGORITHMS

14.4 MESSAGE AUTHENTICATION AND MESSAGE INTEGRITY VERIFICATION

14.5 DIFFIE–HELLMAN KEY ESTABLISHMENT PROTOCOL

14.6 ELLIPTIC CURVE INTEGRATED ENCRYPTION SCHEME (ECIES)

15 PUBLIC KEY INFRASTRUCTURE FOR VEHICLE NETWORKS

15.1 INTRODUCTION

15.2 PUBLIC KEY CERTIFICATES

15.3 MESSAGE AUTHENTICATION WITH CERTIFICATES

15.4 CERTIFICATE REVOCATION LIST

15.5 A BASELINE REFERENCE VEHICULAR PKI MODEL

15.6 CONFIGURE INITIAL SECURITY PARAMETERS AND ASSIGN INITIAL CERTIFICATES

15.7 ACQUIRE NEW KEYS AND CERTIFICATES

15.8 DISTRIBUTE CERTIFICATES TO VEHICLES FOR SIGNATURE VERIFICATIONS

15.9 DETECT MISUSED CERTIFICATES AND MISBEHAVING VEHICLES

15.10 WAYS FOR VEHICLES TO ACQUIRE CRLs

15.11 HOW OFTEN CRLs SHOULD BE DISTRIBUTED TO VEHICLES?

15.12 PKI HIERARCHY

15.13 PRIVACY-PRESERVING VEHICULAR PKI

16 PRIVACY PROTECTION WITH SHARED CERTIFICATES

16.1 SHARED CERTIFICATES

16.2 THE COMBINATORIAL CERTIFICATE SCHEME

16.3 CERTIFICATE REVOCATION COLLATERAL DAMAGE

16.4 CERTIFIED INTERVALS

16.5 REDUCE COLLATERAL DAMAGE AND IMPROVE CERTIFIED INTERVAL

16.6 PRIVACY IN LOW VEHICLE DENSITY AREAS

17 PRIVACY PROTECTION WITH SHORT-LIVED UNIQUE CERTIFICATES

17.1 SHORT-LIVED UNIQUE CERTIFICATES

17.2 THE BASIC SHORT-LIVED CERTIFICATE SCHEME

17.3 THE PROBLEM OF LARGE CRL

17.4 ANONYMOUSLY LINKED CERTIFICATES TO REDUCE CRL SIZE

17.5 REDUCE CRL SEARCH TIME

17.6 UNLINKED SHORT-LIVED CERTIFICATES

17.7 REDUCE THE VOLUME OF CERTIFICATE REQUEST AND RESPONSE MESSAGES

17.8 DETERMINE THE NUMBER OF CERTIFICATES FOR EACH VEHICLE

18 PRIVACY PROTECTION WITH GROUP SIGNATURES

18.1 GROUP SIGNATURES

18.2 ZERO-KNOWLEDGE PROOF OF KNOWLEDGE

18.3 THE ACJT GROUP SIGNATURE SCHEME AND ITS EXTENSIONS

18.4 THE CG GROUP SIGNATURE SCHEME WITH REVOCATION

18.5 THE SHORT GROUP SIGNATURES SCHEME

18.6 GROUP SIGNATURE SCHEMES WITH VERIFIER-LOCAL REVOCATION

19 PRIVACY PROTECTION AGAINST CERTIFICATE AUTHORITIES

19.1 INTRODUCTION

19.2 BASIC IDEA

19.3 BASELINE SPLIT CA ARCHITECTURE, PROTOCOL, AND MESSAGE PROCESSING

19.4 SPLIT CA ARCHITECTURE FOR SHARED CERTIFICATES

19.5 SPLIT CA ARCHITECTURE FOR UNLINKED SHORT-LIVED CERTIFICATES

19.6 SPLIT CA ARCHITECTURE FOR ANONYMOUSLY LINKED SHORT-LIVED CERTIFICATES

20 COMPARISON OF PRIVACY-PRESERVING CERTIFICATE MANAGEMENT SCHEMES

20.1 INTRODUCTION

20.2 COMPARISON OF MAIN CHARACTERISTICS

20.3 MISBEHAVIOR DETECTION

20.4 ABILITIES TO PREVENT PRIVACY ABUSE BY CA AND MDS OPERATORS

20.5 SUMMARY

21 IEEE 1609.2 SECURITY SERVICES

21.1 INTRODUCTION

21.2 THE IEEE 1609.2 STANDARD

21.3 CERTIFICATES AND CERTIFICATE AUTHORITY HIERARCHY

21.4 FORMATS FOR PUBLIC KEY, SIGNATURE, CERTIFICATE, AND CRL

21.5 MESSAGE FORMATS AND PROCESSING FOR GENERATING ENCRYPTED MESSAGES

21.6 SENDING MESSAGES

21.7 REQUEST CERTIFICATES FROM THE CA

21.8 REQUEST AND PROCESSING CRL

21.9 WHAT THE CURRENT IEEE 1609.2 STANDARD DOES NOT COVER

22 4G FOR VEHICLE SAFETY COMMUNICATIONS

22.1 INTRODUCTION

22.2 LONG-TERM REVOLUTION (LTE)

22.3 LTE FOR VEHICLE SAFETY COMMUNICATIONS

GLOSSARY

INDEX

Cover Illustration: © Daimler AG

Cover Design: John Wiley & Sons, Inc.

Copyright © 2012 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data:

Delgrossi, Luca.

 Vehicle safety communications : protocols, security, and privacy / Luca Delgrossi, Tao Zhang.

pages cm. – (Information and communication technology series ; 103)

Includes bibliographical references and index.

 ISBN 978-1-118-13272-2

 1. Vehicular ad hoc networks (Computer networks)–Safety measures. 2. Automobiles–Safety appliances. 3. Automobiles–Collision avoidance systems. I. Zhang, Tao, 1962- II. Title.

 TE228.37.D45 2012

 629.2'76–dc23

2012020858

FOREWORD

Ralf G. Herrtwich

Over the past few decades, vehicles have advanced to assist their drivers in many ways. They brake automatically to avoid accidents, they maintain a perfectly safe distance from the car ahead, they avoid drifting out of lane, and they even evade pedestrians to prevent harm. All these features rely on sensors through which vehicles monitor themselves and their environment. But could these features not become infinitely better if vehicles participated in a little game of “I spy with my little eye … ” and conveyed their own findings to the vehicles around them? Enter vehicle-to-vehicle communication.

In a world where everything is getting connected, the idea of communicating cars is somewhat obvious. However, the first manifestations of vehicle communications that are offered in most premium vehicles today keep humans in the loop: they allow passengers to browse the Internet or their e-mail or let drivers access their vehicle remotely, for example, to readjust the electrical charging procedure. Communicating directly from car to car, from machine to machine, is a whole new ball game, the rules of which are described in this book.

Both Luca Delgrossi and Tao Zhang are pioneers not only in defining but also in implementing vehicle-to-vehicle communication. From the early stages of Department of Transportation (DOT) research projects through Institute of Electrical and Electronics Engineers (IEEE) standardization to the current deployment tests, they were involved in many notable activities that shaped and refined what hopefully is going to become the lingua franca of the vehicle world. I congratulate them on their effort to share their knowledge through this book—because while our vehicles will eventually speak this new language, it is us engineers who have to learn it.

Where will this all lead? Improved vehicle and traffic safety, for sure. Vehicles can communicate dangerous situations to the ones behind them, leading to fewer surprises for drivers through advance warnings—about the end of a traffic jam behind the next curve, a patch of black ice in the next off-ramp, or a stalled vehicle in the right lane. Eventually, driver assistance systems will be able to take such information into account and combine it with their other sensors for a more automated response—reacting to an emergency braking ahead or to a vehicle taking the right of way. On top of this, much of the information collected from vehicles can be used for mobility improvements, and even vehicle efficiency can be increased through a more uniform movement of communicating vehicles. Eventually, vehicles could coordinate their maneuvers with messages, making vehicle-to-vehicle communication an element in the emerging field of autonomous driving.

Not that we are fully there yet, or will be in just a few years. The value of any networking technology grows with the number of entities that can communicate. Reaching a decent population of communicating vehicles on the road is not an easy task, especially because early adopters will be the ones reaping the fewest benefits initially. And there are issues such as security, which may create anxiety among users and thus hinder widespread deployment. It goes without saying that a book covering vehicle-to-vehicle communication in its entirety also addresses these issues.

Enjoy!

PROF. DR. RALF G. HERRTWICHDirector, Driver Assistance and Chassis SystemsGroup Research and Advanced EngineeringDaimler AG

FOREWORD

Flavio Bonomi

It is my special privilege to be able to express a few introductory thoughts on this very timely and important book.

This book, written by two active participants in the research, standardization, and early field deployment of technologies for vehicle-to-vehicle and vehicle-to-infrastructure communications, and of related applications, will quickly become a reference in this field. It provides a clear, organized, and thorough guide into the technology, reaching out to the bleeding research edge, but also into the history, motivations, and applications.

The value of this book is particularly important for our industry, which is starting to understand and act upon the promises of a deep transformation in the field of transportation.

This book is an important testimony of a broad effort, involving academia and industry, led by passionate and visionary leaders, such as Luca Delgrossi and Tao Zhang, who worked for years to bring these technologies to maturity and, hopefully, to pervasive deployment.

Indeed, we believe their effort will find it appropriate manifestation, not only in the traditional road transportation, but also in adjacent sectors.

The technologies and applications described in this book will definitely play an important role in the evolution of smart transportation, smart cities, industrial automation, and, more in general, in the vast explosion of mobile connectivity broadly described as the “Internet of Things.”

Luca, Tao, thanks for your many years of dreaming, research, and evangelization. And thanks for this beautiful work, which will introduce this valuable body of technology to many of the people who will help turn your dreams into reality!

FLAVIO BONOMICiscoFellow, Vice PresidentHead of Advanced Architecture and ResearchCisco Systems

FOREWORD

Adam Drobot

The roles that automobiles play in our global society are as important as ever. Luca Delgrossi and Tao Zhang have written a remarkable book that addresses one of the most important issues in the minds of car designers, public regulators, and consumers: safety and what modern communications can bring to dramatically improve what is possible. This is a complex subject and I have to commend the authors for the lucid and structured approach that they have taken. First, they have brought together the facts about the current status of “safety” of automotive vehicles gathered from many points of view. Second, they have captured the spirit of technological advances and understood that reducing the number of automotive accidents and the consequences of such accidents is a never-ending quest, one that relies on practical adoption of what is available at a given point in time. It is also one in which new tools can be brought to bear as we exhaust the rate of improvement from existing approaches. The heart of these new tools is the exploitation of wireless communications and digital electronics. Third, they have exposed the importance of a multidisciplinary approach. It is one of the reasons that this book is so important: because it melds the fundamentals and subtleties from disparate technical communities. Imagine automotive engineering, safety, wireless engineering, and cyber-security all contributing to one body of work. The promise is a dramatic reduction in the number of automotive crashes; injuries to drivers, passengers, and pedestrians; and destruction of property.

We are at a point in time where the silicon revolution is forcing car designers and manufacturers to significantly reconsider and revise the features and control systems of automobiles. The same is true of the highway infrastructure that our automobiles use. Much of this is driven through the adoption by the public of powerful mobile devices that have ever-growing computing capability, access to stored and real time information, mobile communications, and much more powerful interfaces. They expect the capabilities that have entered their daily lives to show up in their automobiles. This may be for entertainment, convenience, looking after their automobiles, and certainly for safety. A little less visible is the large investment over time in digital sensors and actuators, artificial intelligence, and various subsystems, which are also being built into automobiles and into our highways, and which rely on the economics of replication and mass markets. So looking at an issue such as safety there are several progressions that we can expect. The first is from passive systems to active systems, to eventually autonomous systems capable of safely guiding automobiles with little or no driver intervention. The second is from stand-alone vehicles to ones that interact with other vehicles and with the surrounding infrastructure, to eventually deeply optimized systems that cooperatively share information and rely on collaborative decision making to improve safety and mobility and to reduce the impact on the environment. This is the world of the Internet and the cloud.

For the progressions described above to become reality there is deep technical homework to be done. The topics addressed in this book are the building blocks for completing that homework. They include the architecture of how information is moved and processed within a car, and how the car relies on external information. There is great value to the fact that the topics are dealt with at several levels and that aspects important to safety are clearly identified. The topics include the overarching approaches to vehicle connectivity and how connectivity can be used to satisfy various functions. An important component is the expository description of communication technologies and how they match up to requirements such as latency, jitter, and scalability. Important to all of this are illustrative calculations and simulations that allow the reader to understand why the details matter. One of the most important contributions is the in-depth exploration of security and privacy, and the underlying mechanisms of encryption and key/certificate management. Implementing systems that affect the fundamental controls of automobiles without getting this right is something that would be hard to imagine. At the same time it is important to understand what the issues are and to get to the heart of why satisfying the requirements is so difficult. Last, while we can idealize many of the concepts and analysis of what constitutes a system design for safety, there is nothing better than learning from experimentation and empirical common sense. The authors make it a point to capture what has been accomplished in the field. This is an important book for anyone dealing with research and engineering for connected vehicle systems, and who has a need to know what the underlying technologies are capable of.

In closing this Foreword I would like to congratulate Luca and Tao for writing this book. I know that they live in a world of deadlines and pressures that make it difficult to devote the time and have the discipline to write a book. Nevertheless, they have succeeded at providing us with an excellent work and have contributed to the codification and distribution of knowledge that others can build on. The hard work and late hours that they put in outside their daily duties is visible. The effort they have taken is much appreciated and should be commended.

ADAM DROBOTChairmanOpenTechWorks, Inc.Dallas, Texas

PREFACE

We pay a high price every day in fatalities, injuries, and property damage caused by motor vehicle crashes. While many incremental steps have been taken to improve vehicle safety over the years, the number of vehicles and distance traveled continues to increase, making it more and more difficult to travel safely down the road. Therefore, it is crucial to create new safety systems that can significantly reduce the number of collisions and their severity. Wireless communications may be the cornerstone for these next-generation automotive safety systems.

Over the past decade, engineers have explored ways to use wireless communications to achieve another breakthrough in vehicle safety. Dedicated short-range communications (DSRC) allow for the acquisition of high-quality data that would otherwise be impossible to collect through onboard sensors, providing a rich complement to existing systems. Sharing these high-quality data among vehicles enables them to “see” the complete picture of their surroundings and perceive potential dangers. In 2012, the effectiveness of communications-based safety systems has already been demonstrated through early prototypes and field trials.

This book focuses on communications for vehicle safety. It illustrates the underlying philosophy, design principles, and protocols to build a full wireless communications system suitable for consumer vehicles. It describes unprecedented challenges as well as potential solutions for establishing trust among vehicles, securing data exchanges, and protecting privacy in consumer vehicle networks.

The design of vehicle safety communications systems presents a series of unique challenges. Typical vehicle speeds result in short time intervals for communications, requiring low latencies and fast channel setup. Unlike existing networks, intervehicle exchanges of safety-critical data are dominated by periodic broadcasts of small messages. Traditional mechanisms to improve data transmission reliability, such as packet acknowledgement and retransmission, are no longer effective, because vehicles are constantly moving and delayed packets will likely carry outdated information. Data transmissions occur in widely diverse environments, ranging from urban canyons to hilly terrains and rural areas, each with its unique impact on signal propagation and network performance. Furthermore, communications systems should be able to quickly adjust to highly dynamic vehicle movements and traffic densities.

Similarly, consumer vehicle networks impose unique security and privacy requirements. Vehicles must establish sufficient trust in the messages they receive within the very short time available for data exchanges. Protecting driver privacy introduces conflicting requirements with securing the communications, supporting vehicle safety applications, and detecting misbehaving or malicious entities. Nationwide consumer vehicle networks demand unprecedented system scalability and bring security and privacy management to a significantly higher level of complexity. Many solutions targeted at smaller networks have been found to be nonscalable, ineffective, or inefficient in this context.

Additional constraints are imposed by vehicle requirements. Onboard safety equipment must be built according to automotive grade criteria and be certified. Fixing problems or making changes to in-vehicle hardware or software can incur significant costs and inconveniences to consumers and manufacturers. Finally, the long lifetime of consumer vehicles imposes challenges to ensure backward compatibility between different generations of onboard communication and security systems.

Over the past decade, tremendous collaborative efforts have been devoted to developing vehicle safety communications technology by industry, academia, and government agencies. This book attempts to summarize the main results from these efforts and intends to provide a solid basis for further study. We tried to balance technical details and readability for a broad audience.

BOOK OUTLINE

The first three chapters are dedicated to automotive safety. They introduce the motivation for this work, the context, and the nature of vehicle safety applications. Chapter 1 presents road traffic statistics for the United States, Europe, Japan, and other parts of the world, showing the high price we have been paying in terms of human lives, injured people, and property damage, as well as demonstrating the real extent of the vehicle safety problem. Chapter 2 summarizes the evolution of automotive safety systems, from the introduction of passive features such as seat belts and air bags to active safety and the latest driver assistance systems. Chapter 3 describes vehicle architectures supporting these onboard safety systems, including electronic control units, sensors, and in-vehicle networks. It also discusses vehicle data as well as positioning and security.

Chapters 4 through 9 focus on wireless communications for vehicle safety. Chapter 4 introduces connected vehicles. It discusses vehicle communication modes and applications’ needs, highlighting unique requirements for consumer vehicle networks. In addition, existing technologies are compared to evaluate suitability for vehicle safety communications. Chapter 5 describes allocated spectra for 5.9 GHz DSRC and the wireless access in vehicular environment (WAVE) standard protocol stack. Chapters 6 and 7 illustrate the physical and medium access control layer behaviors, respectively, of the Institute of Electrical and Electronics Engineers (IEEE) 802.11p standard. Chapter 8 presents a study to determine the optimal data rate for DSRC. Chapter 9 presents WAVE upper layer protocols, including the WAVE short message protocol (WSMP) and the IEEE 1609.4 standard for DSRC multichannel operations.

Chapters 10 through 12 illustrate representative safety applications that have been developed and demonstrated as part of recent collaborative efforts. Chapter 10 focuses on vehicle-to-infrastructure (V2I) applications, while Chapter 11 presents vehicle-to-vehicle (V2V) applications. Chapter 12 describes the state-of-the-art research on DSRC scalability and congestion control algorithms for consumer vehicle networks.

Chapters 13 through 21 are devoted to security and privacy protection for consumer vehicle networks. Chapter 13 identifies unique security and privacy threats and requirements in a large-scale consumer vehicle network. Chapter 14 describes the fundamental cryptographic mechanisms that are crucial to supporting security and privacy in vehicle communication networks. Chapter 15 focuses on how public key infrastructures (PKIs) can be extended to manage security credentials such as digital certificates for large-scale consumer vehicle networks, and discusses the issues that need to be addressed to make the use of digital certificates and the PKI privacy preserving. Chapters 16–18 present and analyze three classes of privacy-preserving digital certificate management methodologies: shared certificates, short-lived certificates, and group certificates. Chapter 19 presents ways to extend the solutions presented in Chapters 16–18 to protect driver privacy against potential breaches by the operators of security credential management systems. Chapter 20 is a brief comparison of the three privacy-preserving digital certificate management methodologies presented in the previous chapters. Chapter 21 presents the IEEE 1609.2 standard for supporting security over DSRC networks.

The last chapter of the book, Chapter 22, discusses the use of fourth-generation cellular networks to support selected vehicle safety communication applications.

LUCA DELGROSSITAO ZHANG

ACKNOWLEDGMENTS

Naming all the colleagues and friends who contributed to the research described in this book is a virtually impossible task. At the Crash Avoidance Metrics Partnership (CAMP), we found an ideal environment for fruitful collaborations. Credit has to be given, among others, to Mike Shulman, who serves as CAMP Program Manager. Farid Ahmed-Zaid, Hariharan Krishnan, Michael Maile, and Tom Schaffnit served as principal investigators in a series of national projects and led us through the implementation of always more-refined prototype systems. We gained a wealth of insight and knowledge through interactions with all CAMP engineers. At the Vehicle Infrastructure Integration Consortium (VIIC), we developed the vehicle onboard equipment and the end-to-end privacy-preserving security credential management system for the proof-of-concept trial and debated on policy implications for vehicle safety communications systems. By mentioning Ralph Robinson, Dave Henry, and Tom Schaffnit, all of whom have served as presidents of the VIIC, we intend to acknowledge all VIIC engineers and policy experts. BMW, Chrysler, Ford, General Motors, Honda, Hyundai-Kia, Mercedes-Benz, Nissan, Toyota, and Volkswagen-Audi joined forces at CAMP and VIIC to conduct research in a precompetitive environment.

The Mercedes-Benz team in Palo Alto, California, includes several DSRC pioneers who contributed to this work. Qi Chen and Daniel Jiang developed, in collaboration with Felix Schmidt-Eisenlohr of the Karlsruhe Institute of Telematics, the network simulator 2 (ns-2) that was used to derive many of the results presented in this book. They made their software freely available for networking researchers. Michael Maile led the team that developed the Cooperative Intersection Collision Avoidance System for Violations (CICAS-V) and is one of the world’s experts in V2I systems. Craig Robinson was the lead developer of the Integrated Safety system publicly showcased in 2008. Gordon Peredo, Graham Brown, and Kyla Tirey have years of experience with V2V DSRC systems. They built tens of fully functional prototype systems and public demonstrations with passenger cars and commercial vehicles. Mike Peredo developed software for the roadside infrastructure and took many pictures presented in this book. Tessa Tielert achieved significant breakthroughs with her work on DSRC congestion control and scalability.

The results on privacy-preserving security for vehicular communications are based on close collaborations with many colleagues at Telcordia Technologies, including Stanley Pietrowicz, Hyong Shim, Giovanni Di Crescenzo, and Eric van den Berg. We had fruitful collaborations with many industry partners and automotive suppliers, but special thanks go to Roger Berg, Sue Graham, and the team at DENSO International America, who joined from the very beginning and developed platforms and systems that we are still using today.

Andrew Moran and Yvonne Peredo researched and verified data and facts presented in the first part of the book. John Kenney provided precious comments on an early version of the manuscript. Emma Asiyo and Greg Stevens were instrumental with their encouragement. Finally, we would like to thank our editorial staff: Diana Gialo and Kristen Parrish of Wiley and Stephanie Sakson of Toppan Best-Set Premedia Ltd. for their excellent support.

L.D.T.Z.

1

TRAFFIC SAFETY

1.1 TRAFFIC SAFETY FACTS

Six million crashes involving over 10 million motor vehicles occur on average every year in the United States. In 2009, an estimated 5,505,000 motor vehicle crashes occurred, leading to 33,808 fatalities and 2,217,000 injured people, averaging 93 deaths every day or one every 16 minutes [NHTS11]. Vehicular accidents are the leading cause of death for people between the ages of 3 and 34 in the United States [NHTS09]. These figures account only for police-reported crashes and therefore the actual number of motor vehicle crashes is likely even higher.

A significant percentage of accidents occur at road intersections. In 2007, there were an estimated 2,392,061 intersection crashes, accounting for 39.7% of all crashes in the United States [FHWA09]. Of these accidents, 8061 were fatal and 1,711,000 caused injuries. It has been estimated that, on average, 250,000 accidents every year involve vehicles running a red light and colliding with another vehicle crossing the intersection from a lateral direction [NHTS07].

A recent study estimates the costs of crashes for metropolitan areas of different sizes and populations in the United States [Kitt10]. According to this study, the average annual costs of crashes per person in small, large, and very large metropolitan areas are $1946, $1579, and $1392, respectively. In addition to lost lives, motor vehicle crashes place a heavy economic burden on the society, including increased costs of medical care, disability, insurance, and property damage. In 2000, the annual economic cost to society due to motor vehicle crashes was estimated at around $230 billion in the United States, roughly equivalent to 2.3% of the country’s gross domestic product (GDP) in the same year [NHTS02].

Motor vehicle crashes significantly affect traffic mobility as well. The U.S. Federal Highway Administration (FHWA) estimated that approximately 25% of traffic slowdowns are related to crashes and other traffic incidents. The estimated average annual costs of traffic congestion per person in small, large, and very large metropolitan areas in the United States are $214, $407, and $575, respectively [Kitt10].

1.1.1 Fatalities

Based on historical data published by the U.S. National Highway Traffic Safety Administration (NHTSA) and FHWA, motor vehicle accidents have been responsible for over 3,300,000 fatalities in the United States alone since 1899 [NHTS10]. As the automobile came into greater use, the fatalities increased sharply each year from 1899 to 1931. After remaining stable for a few decades, the annual death rate rose again until peaking at 53,543 in 1969 (Figure 1.1). Since then, the annual number of fatalities has held fairly steady, or even decreased somewhat, due to significant advances in automotive safety measures. With an increasingly mobile society, reducing traffic fatality has become a more difficult task to achieve.

Figure 1.1. Total annual fatalities in the United States

The number of fatalities alone does not paint a complete picture of automotive safety. Since 1899, market penetration of automobiles has continued to increase significantly and the annual number of vehicle miles traveled (VMT) has exploded from 100 million in 1900 to over 3 trillion by 2007, according to FHWA statistics [FHWA07]. The number of fatalities per VMT has actually decreased. In 1921, the United States saw 24 fatalities per 100 million VMT, which were more than 21 times the record low 1.13 deaths per 100 million VMT in 2009.

Broader adoption of effective automotive safety systems, along with improved safety legislation and increased driver education efforts, has powered the reduction of fatalities and injuries despite the growing number of vehicles on the road and the distances traveled. As people continue to travel more, innovations become increasingly crucial to minimize traffic fatality (Figure 1.2).

Figure 1.2. Annual fatality rate per 100 million VMT in the United States

1.1.2 Leading Causes of Crashes

According to NHTSA, the three most common causes of vehicle crashes are: control loss without prior vehicle action, lead vehicle stopped, and road edge departure without prior vehicle maneuver. In 2004, crashes under these circumstances accounted for an estimated 1 million lost functional years and $40 billion in direct economic costs in the United States [NHTS07].

Understanding the events that lead up to a motor vehicle crash is crucial to prevent future crashes. In 2008, the U.S. Congress authorized NHTSA to conduct a National Motor Vehicle Crash Causation Survey [NHTS08]. A representative sample of crashes from 2005 to 2007 was investigated. During the data collection process, the research team was granted timely permissions by local law enforcement and emergency responders to be on the crash scenes. Arriving on the scene before the crash was cleared by law enforcement gave the researchers access to relatively undisturbed information pertaining to the crashes and factors which led to these crashes. It allowed the researchers to discuss the circumstances of the crash with the drivers, passengers, and witnesses while the event was still fresh in their minds. The researchers were able to immediately and accurately reconcile the physical evidence with witness descriptions. Using this and other data, the researchers were able to assess the critical events that preceded the crash, the reasons for this event, and other factors that may have played contributing roles.

Ninety-five percent (95%) of the time, driver error was the critical reason for an accident. Driver errors can be classified into several categories: recognition, decision, performance, nonperformance, and other or unknown driver errors:

Recognition errors accounted for 40.6% of all accidents due to driver error. Inadequate surveillance and driver distraction played a significant role in reorganization errors, accounting for 20.3% and 10.7% of driver error accidents, respectively.

Decision errors accounted for 34% of all driver error accidents. The causes for decision errors were more numerous and varied than for recognition errors. Fast speeds were the most significant, being identified as a critical reason for 13.3% of crashes due to driver error.

Performance errors constituted for 10.3% of all driver error crashes. The primary causes of performance errors are overcompensation and poor directional control. Noticeably, fatigued drivers were twice as likely as nonfatigued drivers to make performance errors.

Miscellaneous nonperformance errors accounted for 7.1% of all driver error crashes. These included sleeping or having medical emergencies such as heart attacks while driving.

Unknown driver errors accounted for the remaining 7.9% of all driver error crashes.

To prevent vehicle crashes, it is also important to understand prominent precrash events. The study has found that 36.2% of all accidents occurred while a vehicle was turning at or crossing an intersection. Traveling off the edge of the road is the second most frequent precrash event, accounting for 22.2% of all crashes. Traveling over the lane line constituted the critical precrash event for 10.8% of all collisions. A stopped vehicle served as the critical precrash event in 12.2% of all cases. Prevention and mitigation of these common causes of accidents therefore take top priority in safety research.

1.1.3 Current Trends

Figure 1.3 shows traffic safety statistics in the United States between 1988 and 2008, including the number of registered vehicles, VMT, injuries, and fatalities. In this chart, each value is expressed as relative to the correspondent value for year 1990. Fatalities and injuries, although declined in recent years, have remained at high levels and the declines have been slow. This raises a concern that we are reaching the point where existing vehicle safety systems are not going to sustain the same rates of reduction in fatalities and injuries as they have in the past. The continuous rise in the number of vehicles on the road and in VMT calls for continuing innovations in vehicle traffic safety technologies.

Figure 1.3. Traffic safety statistics in the United States (1988–2008)

1.2 EUROPEAN UNION

Countries in the European Union have been following a similar trend of increasing automotive safety as shown in Figure 1.4.

Figure 1.4. Annual fatalities in Germany, United Kingdom, and France (2000–2008)

Germany has seen a significant long-term decline in fatalities, with a 79% reduction from 21,332 fatalities in 1970 to only 4477 fatalities in 2008. In addition, the annual number of crashes that caused injuries decreased from 414,362 to 320,614 in the same time period, an improvement of 23%. Remarkably, these declines in fatalities and injuries have been accomplished while the number of vehicles on the road nearly tripled [IRTA10]. These improvements were made possible by a combination of advances in safety technology, a highly developed road infrastructure, an advanced legal framework, and a highly sophisticated penalty point system. Stringent laws concerning intoxicated driving, speeding, and seat belt usage have all contributed to the long-term reductions in accidents and fatalities as well.

Traffic fatalities have also declined significantly in the United Kingdom. Between 1970 and 2008, the annual number of fatalities declined by 66% and the annual number of injury crashes declined by 35%, while the average distance traveled increased by 10% [IRTA10]. These percentages represent a decline from 7771 fatalities in 1970 to 2645 fatalities in 2008 and from 272,765 injury crashes in 1970 to 176,723 in 2008. The United Kingdom’s traffic fatality rate is currently the lowest in the European Union, with 4.3 fatalities per 100,000 people [IRTA10]. As with Germany, the United Kingdom’s improved traffic safety has largely been achieved through advances in safety technology, investments in road infrastructures, and enforcement efforts designed to curb excessive speeding and intoxicated driving. The United Kingdom has likewise placed a significant emphasis on educational programs to raise awareness of high-risk driving behaviors and the sanctions imposed for such behaviors.

France has also seen a significant long-term decline in the overall traffic fatality rate. Between 1970 and 2008, the number of fatalities decreased by 74% (from 16,445 in 1970 to 4275 in 2008) and the number of injury crashes by 68% (from 235,109 in 1970 to 74,487 in 2008) while the number of vehicles on the road tripled. The numbers are even more impressive when you consider the decline in fatalities per billion vehicle-kilometers, which fell from 90.36 in 1970 to a mere 8.1 in 2008, for a total improvement of 91% over that time period [IRTA10]. Further improvements continue to be made. Since 2002, France has implemented a focused road safety policy which includes effective measures regarding speed management, intoxicated driving, seat belt use, and strengthening of the demerit point system, all of which continue to impact traffic safety positively.

As in the United States, the reductions in traffic fatalities and injuries in the European Union countries have slowed down over the recent years (Figure 1.4), which suggests similar diminishing returns achievable through traditional vehicle safety technologies and calls for new thinking and innovation in vehicle safety technologies.

1.3 JAPAN

During the 1960s, the rapid increase in automobile traffic outpaced road constructions in Japan. The resulting increase in motor vehicle accidents became a public concern, prompting the government to take measures to reduce vehicular crashes. In 1970, following enactment of the Traffic Safety Policies Law, the Central Committee on Traffic Safety Measures was established and the first Fundamental Safety Program was formulated. Since 1971, the Central Committee on Traffic Safety Measures has continued to produce 5-year Fundamental Traffic Safety Programs which set forth the fundamental principles and goals for comprehensive and long-term measures for the safety of land, maritime, and air transport based on the Traffic Safety Policies Law.

A cornerstone of Japan’s efforts to improve traffic safety has been a significant investment in road infrastructure enhancement. Safer roads have been achieved through improvements in expressways, bypasses, beltways, intersections, road lighting, road signs, and traffic signals. Safety measures were also enacted for pedestrians, including installation of sidewalks, development of shared pedestrian and bicycle paths, and addition of pedestrian overpasses and underpasses. As a result, pedestrian fatalities have decreased sharply, from 2794 in 1996 to 1943 in 2007, an improvement of approximately 31% [IATS08].

Japan’s traffic fatalities have reduced significantly since the adoption of the first Fundamental Traffic Safety Program. Between 1970 and 2008, the annual number of fatalities decreased by 72% even though the number of injury crashes increased by 7% [IRTA10]. The annual number of fatalities in proportion to distance traveled decreased over that same time span by a remarkable 91% [IATS08]. The declining fatality rate has been sustained in recent years, despite a threefold increase in the numbers of vehicles and VMT. The fatality rate continues to decline as advancements continue to be made in automotive safety, decreasing by approximately 42% between 2000 and 2008 [IRTA10]. This is particularly remarkable and difficult to sustain due to the very high population density in Japan.

1.4 DEVELOPING COUNTRIES

While developed countries have been benefiting from declining traffic fatality rates, this has not been the case in many developing countries such as China and India. Developing countries currently account for 90% of the disability-adjusted life years lost to traffic injuries and deaths worldwide. This problem continues to escalate especially in Asia. It is projected that by 2020, vehicular deaths will increase by 80% in developing countries [KoCr03]. This includes fatality rate increases of almost 92% in China and 147% in India. Injuries due to vehicular crashes are the root cause of a significant portion of medical care sought in developing countries, accounting for up to one-third of the acute patient cases in many hospitals and between 30% and 86% of trauma admissions [OdGZ97]. Besides the toll on human lives, the economic cost of vehicular crashes in developing countries has been estimated at around US$65 billion, a heavy burden on the economy and a financial drain on national health-care systems [PSSM04].

A significant reason that developing countries have not experienced the same reduction in fatality rates as developed nations is that their road infrastructures are unable to keep pace with the sharp increases in the number of vehicles on the roads. This results in unsafe driving conditions and massive traffic congestions. Poor traffic conditions contribute to the prevalent fatalities of vulnerable road users such as pedestrians, bicyclists, and people using carts, rickshaws, mopeds, and scooters. This is in contrast to developed countries, where drivers and passengers are the primary victims [PSSM04]. Vehicles in developing countries are also significantly more likely to be involved in fatal crashes, 200-fold more likely in some cases, than in more developed countries [AATJ10].

Therefore, developing innovative automotive safety technologies is of utmost importance for the world as a whole, not merely for developed countries.

To reduce fatalities and injuries despite the rising number of vehicles and VMT, we must continue to discover new ways to prevent motor vehicle crashes and mitigate their damages.

REFERENCES

[AATJ10] G. Jacobs, A. Aeron-Thomas, and A. Astrop: “Estimating Global Road Fatalities,” Department for International Development (DFID), ISSN 0968-4107, Transport Research Laboratory, Report 445, 2000.

[FHWA07] Federal Highway Administration: “Highway Statistics 2007: Public Road Mileage, Lane Miles, and VMT 1900-2007,” Table VMT-421, 2011.

[FHWA09] Federal Highway Administration: “The National Intersection Problem,” FHWA-SA-10-005, 2009.

[IATS08] International Association of Traffic and Safety Sciences: “Statistics 2007: Road Accidents Japan,” Traffic Bureau, National Police Agency, 2008.

[IRTA10] International Traffic Safety Data and Analysis Group (IRTAD): “Annual Report 2009,” Organization for Economic Cooperation and Development (OECD) International Transport Forum (ITF), 2010.

[Kitt10] M. J. Kittelson: “The Economic Impact of Traffic Crashes,” Georgia Institute of Technology, 2010.

[KoCr03] E. Kopits and M. Cropper: “Traffic Fatalities and Economic Growth,” World Bank Development Research Group, Infrastructure and Environment, Policy Research Working Paper 3035, 2003.

[NHTS02] National Highway Traffic Safety Administration: “The Economic Impact of Motor Vehicle Crashes, 2000,” DOT HS 809 446, 2002.

[NHTS07] National Highway Traffic Safety Administration: “Pre-Crash Scenario Typology for Crash Avoidance Research,” DOT HS 810 767, 2007.

[NHTS08] National Highway Traffic Safety Administration: “Motor Vehicle Traffic Crashes as a Leading Cause of Death in the United States,” DOT HS 810 936, 2008.

[NHTS09] National Highway Traffic Safety Administration: “Traffic Safety Facts 2008,” DOT HS 811 170, 2009.

[NHTS10] National Highway Traffic Safety Administration: “An Analysis of the Significant Decline in Motor Vehicle Crashes in 2008,” DOT HS 811 346, 2010.

[NHTS11] National Highway Traffic Safety Administration: “Traffic Safety Facts 2009,” DOT HS 811 402, 2011.

[OdGZ97] W. Odero, P. Garner, and A. Zwi: “Road Traffic Injuries in Developing Countries: A Comprehensive Review of Epidemiological Studies,” Tropical Medicine and International Health, vol. 2, pp. 445–460, 1997.

[PSSM04] M. Peden, R. Scurfield, D. Sleet, D. Mohan, A. Hyder, E. Jarawan, and C. Mathers: World Report on Road Traffic Injury Prevention, World Health Organization, United Nations, Geneva, Switzerland, 2004.

2

AUTOMOTIVE SAFETY EVOLUTION

2.1 PASSIVE SAFETY

Passive safety features are built into vehicles to minimize driver and passenger harm during a crash. Groundbreaking passive safety features include seat belts and air bags. They have been playing a crucial role in reducing traffic fatalities and have become integral—and in many countries mandatory—features in modern vehicles. The National Highway Traffic Safety Administration (NHTSA) reports that 322,409 lives have been saved in the United States between 1975 and 2008 through the use of child restraints, seat belts, air bags, and motorcycle helmets alone [NHTS09a].

2.1.1 Safety Cage and the Birth of Passive Safety